Windows 10 Pro Preview X64 Build 10061 x64 Full Edition

Official specs of Windows 10 Technical Preview is not much different from Windows 7 and Windows 8.1. For just a reminder, the following official specifications to run Windows 10 Technical Preview:
Processor: 1 gigahertz (GHz) or faster
RAM: 1 gigabyte (GB) (32-bit) or 2 GB (64-bit)
Free hard disk space: 16 GB
Graphics card: Microsoft DirectX 9 graphics device with WDDM driver
A Microsoft account and Internet access
Note!

Technical Preview of Windows 10 is still in BETA version aka probation. Final version of Windows 10 Technical Preview guess work out in 2015 For those of you who have never played with the OS or just understand a little about Operating System, I strongly suggest to download the Windows 10 Technical Preview.

Also Read:

- Explanation Preview version, RTM, Final, OEM, Original MSDN.
Things Before Installing Windows 10 Technical Preview:

Due to Windows 10 Technical Preview is still on probation, I suggest you to install through a virtualization software such as VMware Player VMware Workstation Virtual Box.

However, if you want to install it as the primary OS on your PC, do not forget.

1 Data Backup you [How to Backup Windows 8 / Windows 8.1]
2 Create Recovery disk.
Upgrade to Windows 10 Technical Preview

For users of Windows 7 SP1, Windows 8, Windows 8.1 either 32 bit or 64 bit, you can immediately update directly to the Windows 10 Technical Preview. With Notes, after you upgrade to Windows 10 Technical Preview, you can not go back to your previous OS versions and also can not use the recovery partition to return to the previous OS!
How To Install Windows 10 Technical Preview

1 Download the ISO file under Windows 10 Technical Preview.
2 Burning the ISO file into a 4.7GB DVD-R
3 Install like install Windows 8 / 8.1
4 If prompted for the serial number, use the serial number below:

NKJFK-GPHP7-G8C3J-P6JXR-HQRJR